Combined centrifugal fan and dust collector



April17,11945.- RL. UN LN v 2,373,969

COMBINED CENTRIFUGAL FAN AND DUST COLLECTOR Filed March 5, 1943 2 sheets-sheet i April17, 1945. R L; UNCOLN 2,373,969

JOMBINED CENTRIFUGAL FAN AND DUST QOLLECTOR Filed March 5, 1943 I 2 Sheets-Sheet 2 Patented Apr. 11, 1945 cormrnnn CENTRIFUGAL FAN AND nos'r comno'roa r Roland L. Lincoln, Dover, Mass., assignor to B. r. Sturtevant Company, Boston, Mass.

'- Application March 5, 1943, Serial No. name (Cl. its-e7) -2- Claims. This invention relates to centrifugal fans-comticularly to centrifugal fans having double, involute inlets, with built in dust collectors.

Centrifugal-fans having double; involute inlets are commonly used as induced drait fans, in steam power plants, for example. It is usual to connect separate collectors to the inlets of such fans fr receiving the cinders and fiy ash which would have a corrosive efiect upon the fan blades.

which induce dust free gas from bined with dust collectors and relates more par- There is very little space available in such plants for the usual dust collectors and .for the connecting duct work used-therewith and it is a feature of this invention that a dust collector is built.

into a centrifugal fanthus conserving space yet without detracting from the efliciency of the fan.

An object of the invention is to combine a con trifugal-fan and a dust collector into a single,

efficient, space saving unit.

The invention will now be described with reference to the drawings, of which:

Fig. 1 is a-plan view looking downwardly upon one embodiment of this invention; 1

the hopper into the fan inlets.

The outer, vertical wall l8 interconnects the i'orentry into-the involute inlets l0.

A larger substantially cylindrical segment 24 having a lower wall 25. extends from the segment 23 tothewall I8 and hasthe upper portions 26 which are spaced from and which overlap the lower ends of the walls 22 to form the ejector noz V zles 21, one extending into each of the involute Fi zisa sectional elevation taken along the I lines 2-2 of Fig. 1;

Fig. 3 is a sectional view taken along the lines 015 Fig. 1., and

Fig. 4 is a sectional view taken along the lines 8-4 of Fig. 2.

The double inlet fan illustrated, has the two involute inl'etsll) on opposite sides of the wheel I l and has the usual outlet |2.,

The involute inlets. 10 contain the deflector baflies .13 which are arranged centrallyaround the axial inlets ll to the wheel ll. These baflles serve to cause the dust laden gas to make abrupt.

changes of direction to pass into the axial inlets l4 and thereby to cause the solid particles entrained in the gas to be thrown against the outer walls l5 of the involute inletsl0 whereupon they are skimmed 01! by thetangential skimming passages IG and discharged intothe hopper l1 forming the lower portion of the fan. The usual double inlet, induced draftfan as involute inlets which are separate and distinct and which are not interconnected in the fan. Insuch a fan, the gas entering the two inlets is split outside the fan and supplied separately into the two inlets, as illustrated byl 'ig. 1 of the H. F. Hagen Patent li -1,846,863.

According to a feature of this inventionpthe airsplitter is built into such a double inlet fan and not only serves as an air splitter within the a fan but provides electors communicating with the interior of a dust hopper built-into the fan.

inlets ill. The segment '24 also serves as a splitter in the same way as the segment 23 does and rior of the hopper l1 and serve thrpugh the inductlon action of the gas entering the inlets I 0, to

"maintain a negative pressure in the hopper so that the passage of dust into the hopper through the skimming passage I6 is expedited, and gas from the hopper is recirculated through the fan. The upper wall 28 extends'between the inner walls 22 of the involute inlets I 0 and from the outer wall l8 to theoutlet scroll .29 and forms with. the outlet scroll 2}! between the involute lnlets It, the upper boundary walls of a passage 30 of which the cylindrical wall 25 is the lower boundary and into which the hopper l1 between the involute. inlets ill, opens at its right hand side,

facing Fig. 2 of the drawings.

Thus there being no boundary wall between the interior of the hopper and the passage 30 between the involute inlets I 0, the passage of gas through the involute inlets I'll through the action of the fan wheel H, draws gas from the hopper through the passage 30 and the ejector nozzles 21.

The splitter sheets'forming ejector nozzles arelocated in otherwise unused space between the involute inlets. The hopper extending under the fan wheel requires but little, if any, more space than that from a practical installation view point which is required by the Ian alone. The result is that anjeflicient dust collector is arranged in available, previously unused paces in and around a ran and this without detracting from the emciency of the tan; In fact the overall emciency 1. A fan having inner and outer walls forming opposed invoiute inlet passages, lower walls connected to said outer, walls and forming a dust hopper extending cross-wise said fan and passages below same, means in said passages form-- ing tangential skimmers disoharging'into said,

hopper, other walls connected to said outer walls and forming a common supply passage for said walls for dividing the gas from said common passage into two streams and for guiding same into said inlet passages'and forming a dividing wall separating said hopper from said passagessaid passages between said inner and outer walls and forming with said inner walls ejector nozzles in said inlet passages communicating through said dividing wall with the interior of said hopper for inducing through the flow or gas through said inlet passages, the flow thereintovoi dust free gas from said hopper.

2. A fan having inner and outer walls forming opposed involute inlet passages, lower walls connected to said outer walls and forming a dust inlet passages, and means in said supply passage forming a splitter; sheet connected to said inner 25 hopper extending cross-wise said fan and pa'ssages below same, means in said passages forming tangential skimmers discharging into said hopper, other walls connected to said outer walls and forming a common gas supplypassage for said inlet passages, and means in said supply passage forming a curved splitter sheet connected to said inner walls for dividing the gas from said common passage into two streams and for guiding same into said inlet passages and forming a dividing wall separating said hopper from said passages, said sheet having portions joining smoothly with said inner walls and having other portions extending into said inlet passages between said inner and outer walls and forming with said inner walls'eiector nozzles in said inlet passages communicating through said dividing wall with theinterior of said hopper for inducing through the flow of gas through said inlet passages, the flow thereinto of dust free gas 'sheet having portions'extending into said inlet so m sa ppe ROLAND L. LINCOLN. 

